Conventional underlayment membranes use so-called “dovetail” cavities situated in longitudinal and transverse directions to decrement stress exerted on the external surface of installed flooring tiles, and use grooves formed in longitudinal and transverse directions behind “dovetail” cavities to channel water (such as moisture and vapor) above a subfloor. Additionally, conventional underlayment membranes require fine-mesh screen fabric webbings attached to the underside of the membranes to anchor mortar so that the membranes can be adhered to the subfloor with interlocked mortar formed on the webbings.
These characteristics of conventional underlayment membranes result in several disadvantages. First, the “dovetail” cavities, which have overhangs and undercuts, cause the manufacturing of the membranes to be quite expensive, since specially made machines must be used for the manufacturing. Second, a flooring installer has to apply mortar onto the underside webbings for the webbings to adhere to a subfloor in order to install flooring tiles on the membranes, which is inconvenient and incurs additional installation cost. Third, grooves are formed in longitudinal and transverse directions, although forming channels for water, are still fairly restrictive, as water channeling is restricted to be only along longitudinal and transverse directions.
In addition, the presence of perpendicular grooves may limit the structural integrity of the membrane in such a way that cracks or other defects form along the grooves due to a lack of support from the membrane.
Therefore, there is a need for a self-adhesive decoupling underlayment membrane with a set of water displacement channels that is able to provide appropriate support for flooring or other finished surfaces (e.g., walls, ceilings, etc.).